There has been a known two-dimensional communication system that carries out communication using a sheet shaped sheet device (JP 2006-270165 A). In the two-dimensional communication system, each communication device is provided on the sheet device and communicates with other communication devices through the sheet device.
The conventional communication device for two-dimensional communication includes a signal receiving circuit that receives a signal and a power receiving circuit that receives electric power (Naoshi Yamahira, Yasutoshi Makino, Hiroto Itai, and Hiroyuki Shinoda, “Proximity Connection in Two-Dimensional Signal Transmission,” SICE-ICASE International Joint Conference, Busan, Korea, Oct. 18-21, 2006). A power transmitter and a communication device operate separately between the signal transmission side and the power transmission side, and operation is not linked between them. Power for transmission is significantly large as compared to power for a communication signal. Therefore, the signal transmission frequency and the power transmission frequency are sufficiently apart during signal transmission and power transmission, so that communication signals are not buried in interference from the transmitted power, and a connector for receiving signals and a connector for receiving power suitable for respective transmission frequencies are provided on the signal receiving side and the power receiving side in the communication device.